Advancements in communication technologies have permitted the introduction, and popularization, of new types of, and improvements in existing, communication systems. Increasingly large amounts of data are communicated at increased throughput rates by using such new, or improved, communication systems. As a result of such advancements, communications requiring high data throughput rates, previously unfeasible, are now possible. Communication systems utilizing, or predicated upon, digital communication techniques are, for instance, increasingly utilized better to communicate digital data, and the use of such digital communication techniques has facilitated the increase permitted of data throughput rates.
When digital communication techniques are used, information which is to be communicated is digitized. In one technique, the digitized information is formatted into packets and, once formatted, the data is communicated upon a communication channel, thereby to be transmitted to a destination. Individual ones, or groups, of the packets or frames of data can be communicated at discrete intervals and, once communicated, concatenated together to recreate the informational content contained therein.
Because data formatted in this manner can be communicated at the discrete intervals, a communication channel need not be dedicated solely for the communication of data generated by one sending station to one receiving station, as conventionally required in circuit-switched communications. Instead, a single channel can be shared amongst a plurality of different sending and receiving station-pairs. Because a single channel can be utilized to effectuate communications by the plurality of pairs of communication stations, improved communication capacity is possible.
A conventional LAN (Local Area Network) is exemplary of a communication system in which packets of data are communicated to effectuate the communication of information. WLANs (Wireless Local Area Networks), operable in manners analogous to wired LANs, have also been developed and are utilized to communicate packets of data over a radio link. The IEEE 802.11 standard promulgated by the IEEE (Institute of Electrical and Electronic Engineers) defines an exemplary WLAN communication system, referred hereinafter sometimes as a “WLAN.” In such a communication system, WLAN devices, such as laptop, or other, portable computing devices are connectable to other such devices by way of radio link connections therebetween, such as by way of a WLAN infrastructure. The laptop, or other portable, computing device is, for instance, connected together with a Bluetooth-based, or other radio transceiver. The infrastructure of the WLAN system includes corresponding transceiver devices, referred to as access points, thereby to permit communication of data between the WLAN device and the infrastructure of the WLAN system.
The IEEE 802.11 standard sets forth various system operating parameter requirements. During operation of the WLAN system, for instance, measurements of the power levels of transmitted signals are made. Namely, RSSI (Received Signal Strength Indicator) measurements are made and utilized during operation of the WLAN system. Responsive to such measurements, various operational selections pertaining to various actions are made. For instance, handover of communications with the WLAN device and various radio transceivers, i.e., access points, of the network infrastructure are made responsive to values of the RSSI measurements. Additionally, background scanning, diversity antenna selection, as well as other actions are triggered responsive to values of the measure RSSI levels. Such measurements can further be utilized, for instance, in estimation of coverage areas pursuant to a measuring campaign.
The IEEE 802.11 standard related to a WLAN system, however, does not set forth accuracy requirements related to RSSI measurements of devices operable in such a system. And, the accuracy required in RSSI measurements is dependent upon the action which is to be triggered responsive to the values obtained from such measurements. For instance, the accuracy required of a RSSI measurement is of modest criticality when used to determine whether to effectuate a handover of communications or when selecting which antenna of two, or more, diversity antennas is to be made. The lessened criticality required of RSSI measurement accuracy in such situations is due to the relative nature required of the measurements. That is to say, measurements are made of signals generated by two of the access points of the infrastructure of the WLAN system. In contrast, RSSI measurement accuracy is of increased criticality in, for instance, measurements of coverage areas.
Different WLAN devices are utilized in different manners and the criticality of the RSSI measurement accuracy of such devices is correspondingly different. WLAN devices used in applications in which RSSI measurement accuracy is critical must be calibrated in a manner which permits the RSSI measurement accuracy of the device to be commensurately accurate. Conversely, WLAN devices which are not utilized in applications which require the same level of calibration accuracy do not accordingly need to be calculated with the same level of accuracy. Factory calibration of the WLAN devices at the differing levels of calibration accuracy, depending upon the prospective use of the WLAN device, would be logistically difficult. If, however, all the WLAN devices are calibrated at the high level of RSSI measurement accuracy, additional production time would be required to perform such calibration.
A manner by which to field-calibrate the WLAN device would therefore be advantageous. Only those WLAN devices which require the high level of RSSI measurement accuracy would be calibrated to the high measurement accuracy level.
A manner by which to measure the performance of a WLAN device without requiring the use of expensive or complicated measuring apparatus would also be advantageous.
It is in light of this background information related to the operation of a WLAN, or other radio, system that the significant improvements of the present invention have evolved.